Manufacture of concrete building blocks



June 7, 1932. F STRAUB 1,862,323

MANUFACTURE OF CONCRETE BUILDING BLOCKS Filed Aug. 15, 1951 2 Sheets- Sheet 1 6% lNVEIVTOf.

A TTORNE Y.

I F. J. STRAUB MANUFACTURE OF CONCRETE BUILDING BLOCKS June 7, 1932.

Filed Aug. 15, 1931 2 Sheets-Sheet .2

IN VENTOR. 4&4, I

A TTORNE Y.

win ffi/fllfflllfl Z 6 Patented June 7, 1932 PATENT; orr cs a. srnaun, or new xmrsme'rou, .rmsnvama IANUFAGIUBE OF CONCRETE BUILDING BLOCKS Application fled August 15, 1931. Serial no. sumac.

My invention consists of an im rovement in the art of making concrete bull ing blocks of tamped aggregate. The object in view 1s toprovlde a smooth compact surface by sup-- 5 plemental pressure against the already compacted top surface to further compress and finish the face of the block after removal of surplus aggregate by the usual laterally movable hopper.

In the manufacture of such blocks from coarse rough aggregate, such asvcinders or cinders mixed with other material, water, and a binder, it is possible to secure such a finished surface with certain forms of pressing machines. In tamping machines, however, compressing the material through a laterally movable feeding hopper, surplus material is removed laterally by a planing oif operation, after the tamps have finished their work, and are temporarily elevated.

Such lateral movement of the hopper and its contained surplus ordinarily abrades the exposed surface of the block, leaving it rough, ragged, and unfinished on the normal level, flush with the tops of the usual stationary cores. Such rou h surfaces cannot ordinarily be removed y any practicable smoothing treatment, such as supplemental tamping or pressing, because the block is already compressed to its practical limits of reduction and because, due to the presence of the core terminals, there is no available space for disposition of or re-arrangement of the surface aggregate. y

In my invention, I utilize adjustable cores capable of slight lowering movement, with subsequent compression, and with a resulting further densificationand surface smoothing and exact leveling, such operation produciiig the densified smooth top surface deslre In utilizing the invention, I employ a conventional'form of tamping machine having a filling and surplus removing hopper, means for partly removing core resistance, and pieans for producing the final desired surace.

In the drawings, one-such machine adapted to produce these results as illustrated, inwhich.

Fig. 1 is a vertical sectional view of the machine, showing the charging hopper and tampers in operative position;

Fig. 2is a similar view, showing the hoper moved out of register and the pressing ead in operative position; and

Fig. 3 is a sectional perspective view of a block embodying my improvement.

; In the drawings, 2 is the mold of a'block making machine provided with a laterally '60 movable feeding hopper 3, operable on a plane level with the top of the mold. When the hopper is in register as in Fig. 1, the aggregate delivered by the hopper is tamped by the usual tampers 4 around the cores 5 throughout the mold cavity, the tamped block resting on the usual pallet 6 by which it is elevated for removal when finished.

The tamping operation being completed clear up to the top of the mold, or slightly above, the hopper 3 is moved over by lever 7 to the non-registering position, Fig. 2, shearing off any surplus aggregate level with the-mold top, but at the sametime disturbing and roughening the top of the block, leavinc it with an unfinished surface.

now use the pressure head or finishing plate 8, which is lowered onto the top surface of the block and slightly below the top of the mold, say one-quarter inch. The aggregate so being already compressed to its limit of reduction, the cores 5 are slightly lowered, leaving an upper cavity 9 into whichthe compresed aggregate may flow inwardly around the core, more or less. 35

At the same time, the core or cores 5 being slightly tapered toward the top provide a slight surrounding space when lowered, giving further opportunity for r'e-arrangement or distribution of the aggregate, so that ample provision is thus made for a limited movement of the pressure head 8. Because of the lowering of the cores, the pressure head 8 may be continuously solid and flat' so as to act on the entire top surface of the tamped block, ,without provision of any clearance openings for the core terminals.

The resulting block, as in Fig. 3, shows the upper surface continuously smooth and compact, due to the final pressure thereon, with per 3, any suitable actuating mechanism may be utilized. In the drawings, I show the cores mounted by one'or more rods or posts ex tending upwardly through the base. 11'of the machine, provided with one or more retracting springs 12, engaging washers 13--14, for withdrawing the cores to a limited extent on .such movement. v

For such purpose, a cam 15 may be utilized,

mountedon a rock shaft 16, keyed to lever 7 the'cam engaging the roller 17 at the lower end of post 10.

Thus, when the ho per 3 is in registering position, the cam hol s the core or cores clear up to the top surface of the mold 2, and when the lever 7 and hopper 3 are thrown over out of register, for pressing action by head 8, as in Fig. 2, cam 15 allowsspring 12 to effect receding downward movement of cores 5, to the extent of the depth of the cavity or cavities 9.

I'thus provide forthe lateral distribution of the compacted surface aggregate and its accompanying densification, resulting in the smooth finished surface desired.

For instance, one standard size building -block in common use is nominally 8'x8x 16 inches in dimensions, but the actual depth is 7% inches, so that the compression of the top of say one-quarter inch within a mold eight inches in depth fromits-top to the upper surface of the pallet-brings the block down to suchstandard depth dimensions.

After such operation, the block is elevated in no way limited to theoperation of the specific machine illustrated and above described.

I claim:

1. In the manufacture of concrete ag gate building blocks or the like, the met od herein describedv consisting in tamping the aggregate within a mold around an elevated core, removing surplus aggregate and lowering the core, and then applying pressure to the top of the molded block.

2. In the manufacture of concrete ag regate buildin blocks or the like, the met od herein described consisting in tamping the aggregate within a mold around an elevated core, removing surplus aggre te and lowering the core, and then applying pressure to the to of the molded block to further compress 1ts surface and move a part of the surface aggregate laterally.

3. In the manufacture of concrete aggre-v gate building blocks or the like, the method herein described consistingin tamping the aggregate within a mold around an elevated core, removing surplus aggreate and lower ing the core, and then applying pressure to the top of the molded block to further compress its surface and move a part of the surface aggregate inwardly around the upper core opening.

4. In the manufacture of concrete ag regate building blocks or the like, the met od herein described consisting in tamping the aggregate within a mold around an elevated core, removing surplus aggregate and lowering the core, and then applying pressure to the top of the molded block to, further compress its surface and move a part of the surface aggregate inwardly aroundthe upper core opening and to move lower portions against the sides of the core.

In testimony whereof I hereunto aflix my signature.

FRANCIS J. STRAUB.

or ejected by the usual means operating under the pallet 6 for its removal and drying, leaving the machine ready for the next operation. In the manufacture of building blocks known as cinder blocks, or of other material,

the abrasive action of the under edges of the hopper, cutting through and shearin oil the surplus aggregate under considera le condensation, due to the final tamping, is sevverely disruptive of the material, especially due to the presence of coarse cinder or other aggregate lumps of varving size. The operation above described of re-surfacing and recompacting the face of the block overcomes this serious disadvantage in a highly satisfactory and efficient manner.

It will be understood that the operative mechanism utilized may be varied in different incidents of detail construction b the skilled mechanic, and that the invention is 

